Completing an oil or gas well often includes a cementing procedure that bonds one or more well casings that line a wellbore to a surrounding subterranean formation and bonds overlapping portions of the well casings with each other. In some wells, the cementing process extends from total depth to a surface location, while in others the cement is present only between certain depths. The cement forms an impermeable sheath that prevents the migration of fluids through the annulus surrounding the casing. The cement bonds further enhance the overall integrity of the well. A good cementing bonding and zonal isolation is particularly critical in the case of plug and abandonment operations, especially in deep water applications.
Typically, sonic tools (e.g., cement bond logging tools) or ultrasonic tools (e.g., an ultrasonic pulse-echo scanner) are used in the industry to evaluate the integrity of cement bonds between the formation and the casing. However, the evaluation in these cases uses raw data from only one system of sonic/ultrasonic sensors to infer the cement bonding parameters through indirect methods.